I believe the Z values in the tramming G-code were selected only to prevent dragging the nozzle during travel. Note that the WIki procedures do not specify any gauge thickness. X1 printers do not use a gauge at all; the bed is adjusted so that the nozzle “just touches” the plate.
The sole purpose of tramming is to make the points of the bed directly over the force sensors as equidistant to the plane of nozzle motion as possible. If you want to use a feeler gauge, the gauge thickness does not matter. Metal gauges are fine; the surface of the bed is neither conductive nor electrically charged.
I use a light as a go/no-go gauge because I do not trust my ability to determine the “just touch” point, or to compare gauge drag accurately and consistently. I explained my method earlier in this topic.
Thanks for your response. I also do not have much confidence it “just touches” the plate nor in “gauging”, pun intended, the friction force of a feeler gauge against the nozzle when tramming regardless of what material the feeler gauge is made of.
I’ve seen your comment about using a light instead of a feeler gauge, and it makes sense to use a flashlight to determine the go/no-go on the distance between the bed and the nozzle, and stop once you can “see the light”. What I do wonder is that since the light method would probably allow for a closer than even 0.1mm gap to be dialed in, would this be enough “wide” to prevent scraping the bed between the 3 positions or would a larger gap, say 0.1mm or more, be better suited and safer from that regard?
I think the force sensor in combination with the automatic bed leveling procedure should prevent scraping of the build plate to ever occur as it would build the z-offset map surface during the automatic calibration so the first layer will actually always be deposited at the right distance when printing, so it makes a good adhesion to the build plate.
Funny thing but I just noticed that my A1 Mini has in fact 4 screws on the bed plate and the images shows just 3 screws however I clearly see a fourth screw hole which appears to be empty.
The code also only refers to 3 points so I’m a bit cofused.
I just realized I did not read your initial post carefully enough and assumed you had an X1 series printer since this discussion is in the X series forum category. Since I’ve never seen an A1 Mini, anything I’ve said is possibly invalid.
I did take a look at the A1M tramming code and Wiki. I see that the code tests at four points, and travel clearance is actually 10mm. I am surprised to see that the right-rear support is non-adjustable, the third point to be checked. The only way to change that corner height is by changing one or more of the other three. (Really, Bambu? You couldn’t afford a fourth adjuster?)
I would have expected a fixed support to be the first location tested, not the third, since the other three must be adjusted relative to it. At least then you could use it to experience proper drag with a feeler gauge.
The Wiki needs clarification, and maybe a video. It does not mention using a feeler gauge. It says:
Please make sure that the nozzle is just touching the printing surface**. The nozzle should not push against the printing surface, and there should be no gap between the nozzle and the bed
But the picture of a correct adjustment specifies “almost” touching and shows a visible nozzle-bed gap.
The “light method” may not work with the A1M. You could try it together with a 0.1 mm feeler gauge at the right rear (X179 Y179) and see. Or closer to the right rear support hole location. Or see what happens with slightly smaller or larger gauges.
We may also be too picky about what is close enough, and should just let the automatic levelling do its job.
Thanks for the link to the A1 Mini forum. Obviously I have a better chance of finding a consistent procedure there. Luckily I don’t need one, yet, but as with the other 3D printers I had I suspect that is just a matter of time and after all tramming is regular tuning which should be properly documented and repeatable. After all the printer was trammed when it left the factory so there is a way apparently.
I’ll see what I can find on the A1 Mini dedicated section.
